I was at the local office supply store this past weekend to buy some shipping tape. I automatically looked to the larger size of heavy duty tape: $6.99 for 43 yards. Then I looked at the smaller size and noticed it was $3.29 for 30 yards. I had to do the math in my head a couple times to be certain … and sure enough, it was cheaper (per yard) to buy the smaller size.
With a calculator, we see that the large size is about 16¢ per yard, while the small size is about 11¢.
An easy quick check: Double the price of the small size, $3.29 × 2, and the result is less than $6.99; double the quantity, 30 yards × 2, and the result is far more than 43 yards. If you buy two of the small size, you pay less than the price of the large size and you get more.
It appeared that both items were being offered at their normal price. Nothing to indicate that either was discounted for a special sale.
Which raises the question: Did the store make a mistake, pricing the large size at too high a price or the small size at too low a price? Or, maybe did they figure out that a lot of people reach for the larger size, assuming they are getting a better deal without actually comparing and checking, and knowing this, the store can make some easy extra profit by pricing the large size at a higher cost per unit?